Process for obtaining polymeric silicon compounds



Patented May 4, 1948 ilNlTED sures PATENT OFFICE PROCESS FOR OBTAININGPOLYMERIC SILICON COMPOUNDS William E. Haniord, Easton, Pa., assignor toE. I. du Pont de Nemcurs & companyywilmington,

Del, a corporation of Delaware No Drawing. Application July 23, 1945,Serial No. 606,703

g Claims.

This invention relates to new silicon-containing products and moreparticularly to new polymeric silicon compounds. Still more particularlythe invention relates to polysilicon esters.

This application is a continuation-in-part of my application 8. N.339,178, filed June 6, 1940, now Patent Number 2,386,793.

There has not been previously described any having the value of from 1to 3.

This reaction can be illustrated by the formabon dihalosilicane by whichreaction there is produced a. linear polymer which has the recurring Thereaction can be carried out by contacting the silicane and polyhydriccompound at room temperature or below and up to temperatures as high as400 C. In order that the reaction should not .be unduly slow it isdesirable that the reaction temperature be at least 25 C. and preferablybetween 30 C. and 300 C. The reaction is readily carried out in thepresence or absence of an inert solvent or diluent.

The following examples, in which the parts are by weight furtherillustrate this invention.

Example I of fully hydrolyzed polyvinyl alcohol, and 36 parts heated at40 C. for 24 hours. ride was liberated during the reaction. The mixturewas cooled and the material removed by filtration and washed withmethanol. The powder was insoluble in chloroform, methanol, benzene,

Hydrogen chlosilicon.

remove unreacted silicon halide.

75% aqueous acetic acid, water and 1 normal aqueous sodium hydroxide. Itcontained 4.35%

Example II A mixture of 300 parts of chloroform, 8.5 parts of fullyhydrolyzed polyvinyl alcohol and 27 parts of methyl silicon tr-ibromidewas'stlrred at room temperature for 2 hours followed by heating withstirring for 2 hours at to C. with the liberation of hydrogen bromidethroughout the heating period. Thirty parts of methanol was then addedand the mixture heated to reflux to After cooling the product wasfiltered, washed with methanol and dried at 100" C. The productcontained 5.94% silicon and was insoluble in the solvents mentioned inthe previous example;

Example III A mixture of 250 parts chloroform, 11 parts l-ullyhydrolyzed polyvinyl alcohol and 26.5 parts dimethyl silicon dibromidewas stirred at room temperature for 1 hours followed by stirring for 1hour at 45 to C. During the reaction hydrogen bromide was liberated. Themixture was filtration and washed with methanol. After drying at 50 C.there was obtained 18 parts of a tan powdery product which had a siliconcontent of 7.68%.

Example IV A mixture of 4.4 parts fully hydrolyzed polyvinyl alcohol, 6parts ally] silicon trichloride and 16 parts benzene was heated at C.for 2% hours The reaction product was removed by filtration, washed withmethanol and dried at C. There was obtained 4.8 parts of the allylsilicon derivative which was insoluble in boiling water.

Example V A mixture of 4.4 parts of fully hydrolyzed polyvinyl alcohol,9 parts of an allyl silicon chloride which boiled at 94-95" C. and 16parts of benzene was heated at 70 C. for 2 hours. The reaction productwas removed by filtration. washed with methanol and dried at 100 C.There was obtained 4.7 parts of a brown powder which was insoluble inboiling water.

Example VI A mixture of 3 parts analytical grade soluble" starch, 6parts allyl silicon trichloride and 16 parts benzene was heated at 70 C.for 2 hours. The reaction product was removed by filtration, washedthoroughly with methanol and dried at 100 C. The yield of the allylsilicon derivative of starch was 3.3 parts. The product was a dark graypowder insoluble in boiling water.

. These latter polymers are charac aliphatic, or conand aliphatic groupsand can unsaturated. For instance the hon radical tain both aromatic besaturated or p owl. am tolyl, 'xylyl, or halosilicanes, being readilyavailable, are preterably used in the preparation of thesilicon-containing compounds described herein. The correspondingfluorine and iodine halosilicanes, for example, diethyl silicondifluoride and dimethyl silicon-diiodite can also be used. Thesehydrocarbon silicon halides can be readily obtained by reaction of thecorresponding silicon tetrahalide with a Grignard reagent. By varyingthe amount of Grignard reagent with respect to the silicon tetrahalide,the amount of halogen in the resulting hydrocarbon silicon halide islikewise varied. It is evident that the Grignard reagent may contain inthe organic portion inert linkages such as an ether linkage although itis preferred that the reagent has a hydrocarbon radical.

Th polyhydric alcohol with which the above hydrocarbon halosilicanes arereacted can be either monomeric or polymeric. Examples of thesealcoholic compounds include polyhydroxyalkanes, polyhydroxycycloalkanes,and polyhydroxyalkenes such as ethylene glycol, glycerol, butyleneglycol, pentamethylene glycol, hexamethylene glycol, pentaerythritol,sorbitoi, mannitol, inositol, 1,4-dihydroxybutene-2, polymericpolyhydroxy compounds including polyvinyl alcohol, hydrolyzedinterpolymers of a vinyl ester with a polymerizable compound possessinga single ethyienic double bond such as hydrolyzed vinyl acetate-ethyleneinterpoiymers. It is preferred that the polyhydric alcohol be free fromacidic or similar groups which would react with the silicone. I

It is to be understood that silicon containin materials are obtainedwhen any hydrocarbon silicon halide is reacted with a polyhydricalcohol. When the silicon halide is a dior tri-halide, polymericmaterials are obtained even i! a monomeric polyhydric alcohol is used.Thus, with ethylene glycol and a monohydrocarbon-trihalosilicane, theproduce would be a crosslinked polymer having a stucture such as shownin the following:

a -cnicH=-o-si-o CHQCHFO-l-O- -o-si-o- The polymers resulting from sucha reaction are inert and generally iniusible. As previously mentioned,the reaction of a dihydrocarbondihalosiiicane with a dihydric alcohol isa linear polymer. by their ability to be dissolved and applied fromsolution as coating compositions, impregnating agents and adhesives. Thehighly polymeric linear polyesters can be spun into filaments and iormedinto polymeric halide nlms.

Although the trihydrocarbonmonohalosilicane is reacts with polyhydricalcoholic materials, it is evident that they will not condense with amonomeric hydroxy compound to term a polymer but give the correspondingtrihydrocarbon silicon esters. The monohalosilicanes will react with aor high molecular weight hydroxyi containing material to give asilicon-containing modified substance. By this reaction, such materialsas wood, cotton, viscose, rayon, starch, polyvinyl alcohol, ethylcellulose, etc., can be modified to give silicon-containing materialswhich exhibit such properties as increased resistance to water and tochemical reagents.

A mixture of hydrocarbon halosilicanes can be reacted with a polyhydricalcohol to give a modifled product. These mixtures oihydrocarbonhalosilicanes can be obtained directly by the 'reaction of aGrignard reagent with a silicon tetraand the hydrocarbonhalosilicanesformed will have a halogen content of from 1 to 3. By varying the amountof each of the monohaio, dihaio and trihalo silicanes in the propertiesoi the polymeric silicon ester resulting may be varied, from liquids toinsoluble and diillcultly fusible solids, depending on the polyhydricalcohol used.

As many apparently widely diflerent embodiments of this invention may bemade without departing from the spirit and scope thereof, it is to beunderstood that I do not limit myself to the specific embodimentsthereof, except as defined in the appended claims.

I claim:

1. A process for obtaining a silicon-containing product comprisingreacting a substance, which contains a plurality of alcoholic hydroxylgroups attached to a hydrocarbon residue, with a hydrocarbonsiiicanehalide having the formula RnSiXi-n, where n is a positiveinteger of from 1 to 3, X is halogen, and R is a hydrocarbon radical,the ratio by weight or said substance to said silicanehalide being fromabout 1:1.4 to 1:33.

2. The process set forth in claim 1 in which said substance is polymer.

3. A process for obtaining a polymeric siliconcontaining productcomprising reacting a substance, which contains a plurality oi alcoholichydroxyl groups attached to a hydrocarbon residue, with a dihydrocarbondihalosilicane having the formula RaSiXa, where X is halogen and R is ahydrocarbon radical, the ratio by weight of said substance to saiddihydrocarbon dihalosilicane being from about 1:1.4 to 113.3.

4. A process for obtaining a polymeric siliconcontaining productcomprising reacting a substance, which contains a plurality of alcoholichydroxyl groups attached to a hydrocarbon residue, with a dihydrocarbondihaiosilioane hav- REFERENCES CITED The following references are ofrecord in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,182,208 Nason Dec. 5, 19392,306,222 Patnode Dec. 22, 1942 mixture, the

Certificate of Correction Patent No. 2,441,066. I May 4, 1948;

WILLIAM E. HANFORD It is hereby certified that error appears in theprinted specification of the above numbered patent requiring correctionas follows: Column 4, line 45, for the word "polymer read polymeric; andthat said Letters Patent should be read with this Sgfirection thereinthat the same may conform to the record of the case in the Patent Signedand sealed this 29th day of June, A. D. 1948.

THOMAS F. MURPHY,

' Assistant Commissioner of Patentn.

